Refrigeration equipment for making ice on or within refrigerated tubes has been known for many years. The present invention is an improvement over that disclosed in my U.S. Pat. No. 2,870,612 entitled Ice-Making Apparatus. In that patent, in order to release the ice, the freezing tubes were isolated from the evaporator and hot gaseous refrigerant was employed to force all of the liquid out of the tubes and to raise the pressure. Such system inherently involves a delay in removing the liquid from the tubes and in bringing liquid back into the tubes for ice-making during each cycle.
Other patents in the art include U.S. Pat. Nos.: Williams 2,618,129; Chapman 2,807,152; 2,739,451 and 2,807,150; Kocher 3,053,058; Lowe 3,280,585; Gordon 3,769,812; Hamner 4,094,168; Nilsson et al 3,206,945; Kubaugh 2,239,234; and Dixson 3,435,633.